For high-strength aluminium alloys of this type, such as alloys from the 7075 group, it is known that fusion welding processes such as arc welding cannot be employed successfully on account of the copper content in the alloys. Therefore, use is commonly made of more complex processes for joining these metals.
By way of example, U.S. Pat. No. 5,769,306 discloses a special friction welding process for aluminium alloys of this type.
Japanase Patent Publication JPH1147959 A discloses friction stir welding for high-strength aluminium alloys.
Particularly in vehicle construction, it would be desirable for it to be possible to produce lighter vehicle bodies by joining, for example, steel and high-strength aluminium and to replace relatively heavy steel parts with high-strength aluminium parts. These high-strength aluminium alloys, in particular aluminium alloys from the 7075 group, have been used to date predominantly in aircraft construction, in which case they are riveted—and therefore the problem of the lack of weldability arises to a lesser extent in aircraft construction.